Synchronizing apparatus



Nov. 4, 1930. BANY ET AL 11,789,667

SYNCHRONIZING APPARATUS Filed Nov. 30, 1928 F'i g. t 3

:4 29 r 54 2o ,5 X f Inventor:

\ Herman Being,

\IZ Gordon R-MC Donald bld Theiw Attorney- Patented Nov. 4, I930 UNITED STATES PATENT OFFICE HERMAN BANY, OF YEADON, EPENNSYLVANIA, AND GORDON B. MCDONALD, O1

SGHENEC'IADY, NEW YORK, ASSIGNORS PORATION OF NEW YORK TO GENERAL ELECTRIC COMPANY, A GOR- SYNCHRONIZING AIEIPARATUS Application filed November 80, 1928. Serial No. 322,788.

Our invention relates to improvements in synchronizing apparatus and has for an object to provide improved synchronizing apparatus for automatically controlling the operation of connecting two alternating current circuits whereby to minimize the possibility of effecting a connection at the wrong instant.

In order to produce the minimum of disturbance, two alternating current circuits should be connected when their electromotive forces are substantially alike in phase and in frequency. To this end, it is desirable that the closing operation of the connecting means should be started when the frequency difference is small enough and sufiiciently ahead of phase coincidence to allow for the time necessary to make the connection. In view of the possibility of a sudden change in the fre- O quency difference between the electromotive forces of the circuits, .it is desirable not to start the closing operation until the frequency difference has reached some satisfactory semblance to uniformity. Otherwise, a subsequent sudden change in the frequency difference may result in a disastrous closing. Moreover, it is desirable to'take into account the possibility of the failure of parts of the apparatus so as to eliminate the possibility of a bad connection because of such failure.

In accordance with our invention, we provide synchronizing apparatus which insures a practical check not only on the condition of.

the apparatus but also on the uniformity of the frequency difference.

explanatory of the operation of the embodiment of our invention shown in Fig. 1. V

For the purpose of illustration, we have shown in Fig. 1 an embodiment of our inyention as applied to a three phase alternatmg current electric system including an alternating current circuit such as a bus 3 to which may be connected, by any suitable circult controlling or switching means 4, another alternating current circuit 5 herein shown as including a generator 6. The switching means 4 may be of the latched closed type, and, as shown, includes a closing coil 7 whose circuit is arranged to be energized from a control bus 8 through the contacts 9 of a control relay 10 which is illustrated as instantaneous closing and time delay opening to allow for the time necessary to insure the latching of the switching means. lhe purpose of the control relay 10 is to relieve the more delicate contacts of the electroresponsive apparatus, hereinafter described and embodying our invention, from the heavy duty involved in directly controlling the circuit of the closing coil 7. Included in the circuit of the control relay 10 for opening the circuit thereof upon closure of the switching means 4. is an auxiliary switch 11 associated with the switching means and arranged to be closed when the switching means is open and vice versa.

For controlling the control relay 10 and through this relay the switching means 4: so as to start the closing operation thereof in time to effect closure when the electromotive forces of the circuits 3 and 5 are substantially alike in phase and frequency and only when the apparatus is functioning satisfactorily and the frequency diiference is reasonably uniform, we provide in accordance with our invention eflectroresponsive means-controlled in accordance with the phase difierence and the diflerence between the frequencies of the electromotive forces of the circuits 3 and 5 such that the closing operation of the switching means 4 is started at a predetermined phase difference when the frequency difierfactory period and the apparatusis incondistart the closing operation of tion to function as intended. The electroresponsive means shown in the illustrated embodiment of our invention includea plurality of relays 12,13, 14 and 15 which are connected to be energized from the circuits 3 and 5 and arranged so. that their respective movable members 16, 17, 18 and 19 must-simultaneously be in predetermined positions in order to the connecting means. 5

The relays 12 and 13 are disclosed in United States Letters Patent 1,680,708 and 1, 680,754, dated August 14, 1928. These relays are of the induction disk type, their respective disks 16 and 17 being controlled by opposing shaded pole motor elements 120, 121 and 130, 131

respectively. In order that the movement of the disks may be dependent upon the phase difference between the electromotive forces of the circuits 3 and 5, the motor elements 120 and 130 are arranged to be energized in accordance with the sum of these electromotive forces and the opposing motor elements 121,

- 131 in accordance with the difference between the electromotive forces through suitable means including potential transformers 20 and 21. When the difference between the torques exerted by the motor elements 120 and 121 exceeds a predetermined value, the disk 16 is actuated to move its contact controlling member 22 substantially instantaneously through its predetermined position to close the cooperating contacts 23 at a predetermined phase difiference, In order that the movable member or disk 17 of the relay 13 may be responsive to the frequency difference between the electromotive forces of the circuits 3 and 5 it is retarded by suitable means such as a drag magnet 24 so that the contact controlling member 25 is able to move to its predetermined position and bridge contacts 26 within a predetermined range of phase difference when the frequency difierence is less than a predetermined value for a time sufiicient to permit the necessarymovement. The rela 14, as shown, is substantially similar to t e relay 13 except that, in accordance with our invention, the opposing motor elements 140, 141 are arranged to move the contact controlling member 27 to bridge the cooperating contacts 28 in a shorter time for a given frequency difl'erence and over a predetermined range of phase diiference overlapping that of the relay 13. For this purpose the retardation of the disk 18 by suitable means such as a drag magnet 29 may be less 7 than the retardation of the disk 17 and the shaded poles of the motor elements 140, 141

may be suitably adjustedto provide a differ- 'ent phase difference range. I I

In accordance with our invention, the relay 15 is of 'a type responsive to the phase difference between the electromotive forces of the circuits 3 and 5 and is arranged to tend to actuate its movable member 19 to its predetermined position within a predetermined range of phase difference overlappinga portion of the phase difference range commonto the relays 13 and 14. For this purpose, the relay 15 may be of the pivoted armature type and, as shown, includes a fixed magnetic member 30, an energizing winding 31 and a pivoted hrmature 19 which is arranged to bridge contacts 32 through a contact controlling member 33. The energizing winding 31 is connected to be energized in accordance with a function of the electromotive forces of .the circuits 3 and 5. As shown, this function is the vector difference of the electromotive ranged to be energized from the control bus 8 and including conductors 34, 35, 36, 37, 38, 39, 40 and 41 such that when all the connections are made, the closing operation of the switching means is started through an auxiliary relay 42 which has its winding in this control circuit and which is arranged to control the circuit of the control relay 10. As shown the conductors 36, 37 '38, 39 and 40 are arranged when the contacts 23, 26, 28 and 32 are closed to short-circuit'a current limiting means such as a resistance 43 in series relation with the auxiliary relay 42 to effect the operation thereof. In this manner it is possible to reduce the duty on the contacts of the synchronizing relays 12, 13, 14 and 15 and at the same time to have the relay 42 in effect initially magnetized not sufliciently to permit of its being picked up but great enough to expedite action of the relay at the desired instant. When the switching means 4 is closed, the circuits of both the auxiliary relay 42 and the control relay 10 become deenergized through the opening of the auxiliary switch 11. The 0 eration of our invention will be apparent rom a consideration of the vector diagram shown in Fig.2 in which OE is motive force of the bus. The relay 13 is arranged to close its contacts 26 within a ran e of phase difierence represented by the ang e 13'E13" when the frequency difference is less than a predetermined value. Similarly, the

relay 14 is arranged to closeits contacts 28 within a range of phase difi'erence represented by the angle 14'E14" when the fredifference 14'-15 quency difierence is less than a predetermined value. The phase difierence ranges for the relays 13 and l4 overlap and the relay 14 is retarded to a lesser extent than the relay 13 so that it can operate to close its contacts 28 in a shorter time than the relay 13 fora given frequency difference. The relay 15 is arranged to tend to close its contacts at the phase diiierence indicated by the vector -15 and within a range of phase difference measured clockwise from the vector 015 to the vector 0-15 which may be prior to phase coincidence. This relay therefore, tends to have its contacts closed over a range of phase difi'erence represented by the angle 14'15 which overlaps a portion of the range of phase difierence common to the relays 13 and 14. Within the range of phase common to the relays 12, 13 and 15, the relay 12 is arranged to effect a momentary closure of its contacts 23 at some predetermined phase difference indicated for example by the vector O12. 1n the discussion herewith, it is assumed that the vector representing the electromotive force of the circuit is rotating clockwise, but the apparatus embodying our invention functions in similar manner whether the frequency of the circuit 5 is less or greater than that of the circuit 3.

-IV hen the frequency difierence between the electromotive forces of the circuits 3 and 5 is such that the relays 13 and 14 can close their contacts prior to the phase difference 0-12 and the relay 15 has its contacts closed, then the control circuit for the auxiliary relay i2 is energized sufiiciently to efiect the pick-up of the control relay and thereby the closing of the switching means 4. Although the relay 12 can in its return movement close its contacts 23 at a position represented hy the vector O12, it is inefi'ectivc to accomplish anything at this time since the contacts of the relays 13 and 14 are open. It

will be apparent from Fig. 2 that if the frequency difi'erence at the phase difference 0-13 is small enough to permit the closing operation of the relay 13 and that at some intermediate point prior to the phase difference 0l2 the frequency difi'erence should suddenly increase, the control circuit would not be closed even though relay 13 had closed its contacts before the phase difierence 012 since the relay 1% would not have time to close its contacts ahead of this phase difference position. It will be apparent that if for any reason the contacts of one of the relays 12, 13, 14 and 15 should close and stick, the remaining relays will prevent an improper closing of the switching means 4 since closing can take place only within a relatively limited range'of phase difference when the frequency diii'erence is less than a predetermined value.

While we have shown and described our invention in considerable detail, we do not desire to be limited to the exact arrangements shown, but seek to cover in the appended'claims all those modifications that fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination, two alternating current circuits, means for connecting the circuits and. means for controlling the closing operation of the connecting means including a plurality of relays connectedto be energized from the circuits and arranged so that their movable members must simultaneously be in predetermined positions to start the closing operation of the connecting means, means for retarding the movement of the movable members of two of said relays, means for moving the movable elements of said two relays to their respective predetermined positions in times dependent on the difierence between the frequencies of the electromotive forces of said circuits and within predetermined overlapping ranges of phase difierence between the electromotive forces, means tending to move the movable member of another of said relays to its predetermined position within a predetermined range of phase difi'erence overlapping a portion of the phase difierence common to the movable members of the two relays, and means for actuating the movable member of a fourth one of said relays through its predetermined position at a difference within the range thereof common to the movable members of the first three mentioned relays.

2. In combination, two alternating current circuits, switching means for connecting the circuits, means including a control circuit having a plurality of connections arranged when all are closed to start the closing operation of the switching means, and means for controlling said connections including a plurality of movable members arranged to be controlled in accordance with the phase difierence between the electromotive forces of the circuits, means for retarding the movement of one of said members, means for actuating said member to close its respective connection within a predetermined range of phase difierence when the frequency diii'erence is less than a predetermined value, means for actuating a second of said members to close its respective connection in a shorter time than said first member and within a predetermined range of phase difierence overlapping said first mentioned range when the frequency difference is less than said predetermined value, means tending to move a third of said members to close its connection within a predetermined range of phase diiferen'ce overlapping a portion of the phase difference predetermined phase range common to the first and second movable members and means for actuating va fourth of-said members to effect a momentary closure of its connection at a predetermined phase difference within the range thereof common to the first, second and third movable members.

3. In combination, two alternating current circuits, a switch for connecting the circuits and means arranged when simultaneously in predetermined positions to start the closing operation of the switch includingtwo retarded movable members, means for actuating said members in accordance with the sum of and difference between the electromotive forces of the circuits to move the members to their respective predetermined positions in different times and within different predetermined overlapping ranges of phase difference when the frequency difierence is less than a predetermined value, a third movable member, means for actuating said third member in accordance with the diiference between the electrom'otive forces to tend to move said third member to its predetermined position within a range of phase diiference ending prior to phase coincidence and overlapping a portion of the phase difference range common to the two retarded members, a fourth movable member and means for actuating said fourth member in accordance with the sum of and the difference between the electromotive forces to move said fourth member through its predetermined position substantially instantaneously at a predetermined phase difference within the range thereof lcJommon to the'first three mentioned memers.

4. In combination, two alternating currentcircuits, a switch for connecting the circuits and means arranged when simultaneously in predetermined positions to start the closing 0 eration of the switch including two mova le members, means for actuating said two members in accordance with the sum of and difference between the electromotive forces of the circuits to move said members to their respective predetermined positions in different times and within different predetermined overlapping ranges of phase difference when the frequency difierence is less than a predetermined value, -a third movable member, means for actuating said third member in accordance with a function of the electromotive forces to tend to move the member to its predetermined position within a range of phase difference ending prior to phase coincidence and overlapping a portion of the phase difference range common to said two members, a fourth movable member and means for actuating said fourth member in accordance with the sum of and the difference between the electromotive forces to move the member 

